Technical Field
The present invention relates to a cryogenic refrigerator including a displacer.
Description of the Related Art
As an example of a cryogenic refrigerator which generates an extremely low temperature, Gifford McMahon (GM) refrigerator has been known. In GM refrigerator, using a volume change of a space by a displacer reciprocating in a cylinder using a drive unit, a working gas supplied from a compressor is expanded in an expansion chamber, and thus, cooling is generated.
Accordingly, in the related art, the high pressure working gas generated by the compressor is introduced into the expansion chamber via the displacer, and the working gas, which is expanded in the expansion chamber, is required to be recirculated to the compressor via the displacer.